Furthermore, the invention relates to a field device of automation technology, as well as to a servicing device for parametering such a field device.
In process automation technology, field devices are often applied, which serve for registering and/or influencing process variables. Examples of such field devices are fill level measuring devices, mass flow measuring devices, pressure- and temperature measuring devices, etc. In such case, sensors register the corresponding process variables, such as fill level, flow, pressure and/or temperature.
Serving for influencing process variables are actuators, e.g. valves or pumps, via which e.g. the flow of a liquid in a pipeline section, respectively the fill level in a container, can be changed.
Referred to as field devices are, in principle, all devices, which are applied near to the process and deliver, or process, process relevant information.
A large number of such field devices are produced and sold by the firm, Endress+Hauser.
Known are field devices, which via a 4.20 mA electrical current interface, respectively two-wire line, are integrated into an automation plant. The terminology, integrated, means that the field device is supplied with energy by, and can exchange measured values or also actuating values, with the control system.
Besides such field devices, there are also so called four-wire field devices, which due to their higher energy requirement are integrated into the automation plant via two separate energy supply-lines.
This state wherein the field device is supplied with energy via a two-wire line or a four-wire line will be referred to herein as “online”. In contrast therewith, the state, in the case of which a field device is not connected to a two-wire line and, thus, also cannot be supplied with energy thereby, will be referred to herein as “offline”. Of course, a field device, which is “offline” also exchanges no measured values or actuating values with the control system.
Likewise known is that the way, in which a field device works, is established with the assistance of parameters, which are written into modules provided therefor, respectively into specific memory locations of the field device. By storing suitable parameter values in the respective modules, respectively memory locations, the way, in which the field device works, is established. This procedure is referred to as “parametering”. The setting of the parameters is performed, for example, by the customer. By selecting suitable parameter values, the customer can adapt the field device to its particular application. Such parameters, for example, in the case of a fill level measuring device for measuring the fill level of a medium in a tank, are the height and the diameter of the tank.
The parametering of such field devices takes place, in such case, currently in the “online” state of the field device.
For this, the field device is first physically connected to the two-wire line and then the field device is parametered by means of a service device.
This procedure has the disadvantage that a service technician must be present for the entire parametering at the possibly unfavorable location of installation of the field device, where the field device is connected for energy supply by means of the two-wire line.